Re: I8kfanGUI unistall
Fn/Z could be done at any time, it won't change any settings, on my D830 it does momentarily shut the fan off and then it returns to a speed appropriate to the temperature.
You can observe details with use of these utilities and notice if there has been an unexplained increase in heat.
Most important, would be to clean your cooling system at least monthly, as fans will draw in dust that can be captured by the cooling fins of your Thermal Cooling Assembly.
Best way to do this will vary by system, D800 will drop main fan with two screws. View (from Support top right of this page) your Service Manual, to understand how your systems are constructed.
D830, you can see the fan and cooling fins through the air intake/exhaust, but access is a job best avoided by frequent cleaning through those vents.
Important to prevent high air pressure (like from canned 'air') from overspeeding the fan and damaging fan bearings.